[llvm-branch-commits] [clang-tools-extra] release/20.x: [clangd] [C++20] [Modules] Add scanning cache (#125988) (PR #128841)

[kadir çetinkaya via llvm-branch-commits]

kadircet wrote:

I don't really feel comfortable backporting this change.

it's a significant change with implications on stability, and doesn't really bring any functional improvements to clangd's module support.

i.e. in absence of this patch, we know that module support "works" (well at least doesn't crash). with this patch, nothing will change in terms of functionality, we'll just have "faster" startup times, at the risk of rendering clangd less stable.

i feel like people wanting such optimizations can actually build clangd from head, or use non-official release snapshots (e.g. https://github.com/clangd/clangd/releases).

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All of that being said, @ChuanqiXu9 if you still feel like we should backport this; can you test this version of clangd for a while and ensure we don't have crashes/stability concerns? I'd be OK with merging in such scenario. Also cc @HighCommander4 in case I am not responsive.

https://github.com/llvm/llvm-project/pull/128841